Intrazeolite photochemistry.: 23.: Transparent PDMS films of zeolites incorporating organic guests:: Quantitative determination of photophysical parameters by transmission techniques

Zeolites containing embedded organics have been made into transparent films. These new materials have interesting properties that allow the measurement and quantification of optical and photophysical properties of the guest molecules that are either unattainable using current diffuse reflectance techniques or significantly less quantitative. These include the determination of the ground-state extinction coefficients and the quantum yield of triplet formation. It was determined that within experimental error, the values of the photophysical parameters of the guest molecules included within the zeolite are very similar to those measured in solution. This indicates that in the cases under consideration, incorporation of an organic molecule or cation into the zeolite pores does not significantly alter its molecular properties with respect to those in nonrigid media. These transparent films open the possibility of determining the extinction coefficient of cations that are not persistent in solution but can be formed within the zeolite pores. Further technical applications of these films, which show remarkable stability and fatigue resistance, can also be anticipated.